1. Field of the Invention
The present invention relates to an adaptor for small fluorescent tubes with contact pins. The adaptor comprises a fluorescent tube-compatible socket and an incandescent lamp-compatible, feed-side screw or bayonet cap, an outer casing part with an incandescent lamp-compatible cap, a printed circuit board which is held in the compatible cap and an inner casing part with a fluorescent tube-compatible socket.
2. Description of the Prior Art
The German patent, DE C 2819550, discloses an adaptor suitable for connecting a circular fluorescent tube. This adaptor has an outer casing part with a feed-side incandescent lamp-compatible socket, an inner casing part with a fluorescent tube-compatible socket, and a printed circuit board for receiving a circuit arrangement for electrical matching purposes. This adaptor can also be joined along a joining axis and is rotationally symmetrical. However, the overall design is only for fluorescent tubes of one type. The adaptor would become unusable for changing the electrical or mechanical requirements. The overall construction is extremely voluminous and it is not possible to use an energy-saving fluorescent tube in an existing light fitting, such as hanging or standing lamps. This design would not allow the desired, more widespread use of energy saving lights.
Attempts have been made in lighting technology to obtain the energy consumption savings of fluorescent tubes in place of light bulbs. Thus, for example, fluorescent tubes are known, such as the Osram COMPACTA tubes, which the lighting body comprises a fluorescent body integrated with the electrical ballast and starter necessary for main voltage in a single casing. The casing is provided with a bulb, namely a screw cap, enabling the fluorescent tube to be screwed into conventional incandescent lamp sockets. By integrating the starter, ballast and fluorescent material lighting body in one casing, the lighting elements become heavy and expensive. In the case of a failure of the fluorescent body only, the entire lighting element has to be thrown away, including the completely intact starter and ballast.
In addition, small fluorescent tubes are known which are provided with special caps, in which are fitted solely with the starter and a capacitive ballast. These small fluorescent lamps are much less costly, but cannot be fitted in conventional incandescent lamp caps. Manufacturers of such small fluorescent tubes therefore market inserts, which can be fitted in a fixed manner and cabled to the main voltage supply. Compared with incandescent lamps, the use of fluorescent tubes usually leads to a significant operating savings.